Segment and Revenue Information (Operating Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating income (loss)	$ 501	$ 690	$ 2,424	$ 2,121
Restructuring charges	0	0	(108)	(25)	$ (67)	$ (63)
Merger-related costs and other corporate matters	(80)	(46)	(93)	(65)
Gain on sale of assets	0	0	549	0
Interest expense	(114)	(115)	(346)	(349)
Interest income	12	12	38	43
Other items, net	(24)	(17)	(66)	(52)
Earnings (loss) before income taxes and equity in earnings (loss) of investee companies	375	570	2,050	1,763
(Provision) benefit for income taxes	(33)	(64)	344	(312)
Equity in loss of investee companies, net of tax	(23)	(18)	(52)	(52)
Net earnings	319	488	2,342	1,399
Operating Segments [Member] | Entertainment [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	302	384	1,258	1,237
Restructuring charges			(48)		(27)
Operating Segments [Member] | Cable Networks [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	196	241	556	722
Restructuring charges			(5)
Operating Segments [Member] | Publishing [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	52	51	102	98
Restructuring charges			(5)		(1)
Operating Segments [Member] | Local Media [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	96	124	364	370
Restructuring charges			(28)		$ (18)
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(65)	(64)	(204)	(216)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Restructuring charges	0	0	(108)	(25)
Merger-related costs and other corporate matters	(80)	(46)	(93)	(65)
Gain on sale of assets	$ 0	$ 0	$ 549	$ 0